We often take air conditioning for granted. We simply flip a switch or turn a knob, and eventually the house or office temperature drops. Portable room air conditioners offer even greater flexibility when it comes to cooling specific rooms around the house, lowering the heat anywhere you place it. Knowing how air conditioners work can help you make a great selection when it comes to choosing a portable room air conditioner.

Although there are air conditioners that come in small to very large sizes, they all function based on the same idea. An air conditioner takes the hot air from inside a building and removes it to outside the building through a hose that is attached to a partially opened window or a hole placed in the wall. A fan is used to bring the hot air in the room into the air conditioning unit, and that hot air flows over an evaporator coil. The coil is filled with refrigerant, which absorbs the heat from the air. Now that the air is cool, it flows back into the room through the front air vents on the air conditioner because a fan pushes the cool air out. The heat leaves the room through the hose vent to the outdoors, or to a second section of the unit, which is found in a split unit.

Some air conditioners are also dehumidifiers. This means that the unit takes the excess water from the air in the room, making the effects of high humidity lessen. The water taken in also helps to cool the unit. The unit can cause the water to evaporate due to the hot air taken in, and this type of air conditioner has no tank that will need to be emptied. Other units use the condensed moisture to improve the unit's efficiency, in a method called condensate cooling.

Some air conditioners also function as heaters, thereby providing two useful traits for the price of one. All air conditioners help improve air circulation in stagnant room air. Other units offer filtering options for pollen, dust and dander, which is very helpful to people with health issues such as allergies or asthma.

Two other terms you will see used with air conditioners are BTUs and the energy efficiency ratio. With BTUs, the higher the number of BTUs, then the more powerful the unit is. The energy efficiency ratio is the measurement that tells how cost efficient the unit is to run. A higher rating means that you will pay less in the long run for energy to run the unit.

Portable room air conditioners are available with any of these functions, so you can pick the one that will best meet all of your room air needs.